The New York Times has a great article today on changing attitudes towards CS, driven in part by movies like "The Social Network." Apart from the movie's (glossy and inaccurate) depiction of what it's like to be a hacker, there's something else going on here: the fact that CS students can jump in and apply their knowledge to build great things. At Harvard, countless undergrads taking the introductory CS50 class are producing games, websites, and iPhone apps -- some of which are good enough to turn into commercial products. I don't know of any other field where this is possible after taking just a single semester's worth of courses.
Of course, it wasn't always this way. For a very long time, Computer Science education at most Universities was grounded in the abstract and theoretical. Undergraduates rarely got the opportunity to build "real" applications or products. After all, before the advent of cheap, powerful PCs, a department might have one computer for the entire class, and its main purpose was to sit in a walled-off machine room and spit out numbers on a printout -- hardly inspiring. I did my undergrad degree at Cornell, and the first class I took was taught in Scheme -- a language I have never used since -- although the projects were fun for someone like me (implementing a public key cryptosystem, and doing some neat machine vision algorithms). Of course, this was before the Web, iPhones, and Facebook, so CS class "projects" tended to be somewhat dry back then.
Unfortunately, there are still too many vestiges of this old fashioned approach to Computer Science evident in the curriculum. It is largely a generational thing. At Harvard, I had a hell of a time convincing some of the senior faculty that we should be teaching all CS students the fundamentals of computer systems, like how a process works, what a cache is, how to program using threads. (Of course, like most CS degree programs, Harvard still requires all students to learn the finer points of nondeterministic finite state automata and arcane discrete mathematics. Harry Lewis, who teaches this class, once described this to me as "eating your vegetables.")
A few years ago, I was asked to take over teaching CS50, Harvard's introductory CS course. Since the semester was right around the corner, I didn't have time to revamp the course, and agreed to do it only if I could teach the original course material with few changes. I took a look at the existing syllabus. The first lecture was about the "history of computing" and was full of black and white pictures of Babbage and ENIACS and men in horn-rimmed glasses looking over printouts in a terminal room somewhere. This was not a promising start. The next six lectures explained in painful detail -- down to machine instructions and the bit representation of integers -- how to write a single program: How to convert Fahrenheit to Celsius. This being the only program that students saw for the first month or so of the course, it's no wonder that the course did not have broad appeal. This kind of material probably worked very well in the early 1990's, but not so today -- the field has changed, and what students are looking for has changed too.
Of course, there is a risk in going too far down this fun, project-oriented route. Computer Science is not a vocational program, and it's important for students to graduate with a deep understanding of the field. It's true that you can do amazing things with existing languages and tools without learning much about the deeper theory and foundations. Still, I think it's great to attract students with a fun, application-oriented course that gets them excited about the field, and hit them later with the more abstract ideas that might seem less relevant at the outset.
One problem is that the classes that follow CS50 are nowhere near as exciting -- they don't have monthly pizza parties and free Facebook schwag at the end of the semester -- so keeping students in the program beyond the intro course can be a challenge. But I think it's important for universities to consider where CS undergrads are coming from and try to meet them there, rather than to teach the way it was done 30 years ago, on a PDP-11 running LISP.
Saturday, June 11, 2011
I've posted a story to Medium on what it's been like to work at a startup, after years at Google. Check it out here.
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